of the u.s. conference of catholic bishops, offered benedictions at both the democratic and republican conventions. for months, the bishops have led a vigorous campaign against the obama administration's policy mandating that employers, including many religious employers, offer free coverage of contraceptive services to their employees. the bishops accuse the obama administration of violating religious liberty. it's unclear how much those efforts have changed any opinions among voters. polls show catholics remain deeply divided, and that could be especially important in battleground states such as ohio, pennsylvania and florida. while much of the focus has been on the economy, green says here at the end of the campaign, other social issues may play an important role. >> there's some strong incentives for the parties to reach out for secondary issues. issues like women's rights, religious liberty, the environment, foreign policy. because if voters are evenly divided on their most salient issue, the economy, they're going to make their decision perhaps on some of these secondary issues.